The broad, long-term objective of the parent grant (5 R01 AI42075-04) and this project is to determine the immune and inflammatory responses that have an impact on the pathogenesis of and protection from mycoplasma respiratory disease. In the parent grant, the hypothesis is that T helper cells play a central role in determining the balance between helpful and harmful immunologic responses in murine mycoplasma respiratory disease. Furthermore, this balance is mediated by T cell subsets whose activity is modulated by regulatory cytokines, such as IL-4 and IFN-gamma. In fact, Th cells are proinflammatory while CD8+ T cells were found to unexpectedly dampen the inflammatory disease due to mycoplasma infection. In addition, the results demonstrate that IFN-gamma plays a novel but an important regulatory role in innate immunity against mycoplasma. These results indicate that the immune mechanisms involved in this disease are complex and require a broader understanding of the regulatory cytokines produced during disease pathogenesis and their regulation by T cells and cytokines. Thus, the current studies are proposed to establish whether a broader, more exploratory approach to analyze production of cytokines can facilitate our understanding their modulation and their potential role in mycoplasma respiratory disease. The Specific Aims address the following questions: 1) What cytokines are produced in lungs of normal or IFN-gamma deficient mice at different stages of mycoplasma disease?; and 2) What is the impact of CD4+ and CD8+ T cells on pulmonary cytokine production? The methods to be used in this exploratory approach are to first monitor cytokine mRNA production using array technology, and those cytokine mRNAs, shown modulated using arrays, will be further analyzed for their levels of expression and for experimental variations using real-time RT- PCR analysis. Furthermore, cytokine protein arrays will be developed to assess their production in a microarray format; once established tissue homogenates and cell culture supernatants to do this, we will develop assays using pre-existing antibodies to capture and detect cytokine protein in an array format. Thus, by analysis of a broad number of cytokines, clusters of cytokines with similar and/or contrasting regulatory properties should be identified that are associated with disease progression for further functional analysis.